Commit 9a6c0e28 authored by Jason Gerecke's avatar Jason Gerecke Committed by Benjamin Tissoires
Browse files

HID: wacom: Use ktime_t rather than int when dealing with timestamps 

Code which interacts with timestamps needs to use the ktime_t type
returned by functions like ktime_get. The int type does not offer
enough space to store these values, and attempting to use it is a
recipe for problems. In this particular case, overflows would occur
when calculating/storing timestamps leading to incorrect values being
reported to userspace. In some cases these bad timestamps cause input
handling in userspace to appear hung.

Link: https://gitlab.freedesktop.org/libinput/libinput/-/issues/901


Fixes: 17d793f3 ("HID: wacom: insert timestamp to packed Bluetooth (BT) events")
CC: stable@vger.kernel.org
Signed-off-by: default avatarJason Gerecke <jason.gerecke@wacom.com>
Reviewed-by: default avatarBenjamin Tissoires <benjamin.tissoires@redhat.com>
Link: https://lore.kernel.org/r/20230608213828.2108-1-jason.gerecke@wacom.com


Signed-off-by: default avatarBenjamin Tissoires <bentiss@kernel.org>
parent 4c221672

drivers/hid/wacom_wac.c

+3 −3
Original line number Diff line number Diff line
@@ -1314,7 +1314,7 @@ static void wacom_intuos_pro2_bt_pen(struct wacom_wac *wacom) 
	struct input_dev *pen_input = wacom->pen_input;

	unsigned char *data = wacom->data;

	int number_of_valid_frames = 0;

	int time_interval = 15000000;

	ktime_t time_interval = 15000000;

	ktime_t time_packet_received = ktime_get();

	int i;
@@ -1348,7 +1348,7 @@ static void wacom_intuos_pro2_bt_pen(struct wacom_wac *wacom) 
	if (number_of_valid_frames) {

		if (wacom->hid_data.time_delayed)

			time_interval = ktime_get() - wacom->hid_data.time_delayed;

		time_interval /= number_of_valid_frames;

		time_interval = div_u64(time_interval, number_of_valid_frames);

		wacom->hid_data.time_delayed = time_packet_received;

	}
@@ -1359,7 +1359,7 @@ static void wacom_intuos_pro2_bt_pen(struct wacom_wac *wacom) 
		bool range = frame[0] & 0x20;

		bool invert = frame[0] & 0x10;

		int frames_number_reversed = number_of_valid_frames - i - 1;

		int event_timestamp = time_packet_received - frames_number_reversed * time_interval;

		ktime_t event_timestamp = time_packet_received - frames_number_reversed * time_interval;



		if (!valid)

			continue;

drivers/hid/wacom_wac.h

+1 −1
Original line number Diff line number Diff line
@@ -324,7 +324,7 @@ struct hid_data { 
	int ps_connected;

	bool pad_input_event_flag;

	unsigned short sequence_number;

	int time_delayed;

	ktime_t time_delayed;

};



struct wacom_remote_data {